16 July 2006

The Prowling Naturalist: Sierra Norte de Oaxaca: Setting Traps for a Puma

Much of the land around La Cumbre is communally managed by the local people, who are all of Zapotec origin. There are extensive forests which were logged from 1956 to 1982 before the community regained control of their land. The forests have recovered remarkably well thanks to active restoration efforts (e. g., seed trees, tree planting) by the community [1]. Scattered farms, often growing corn, are interspersed with the forests. Some areas are still logged selectively, with native pines being the only timber of commercial importance. Oak and other trees are only harvested for local use, mainly as firewood. In many years, the annual quota (12 900 cu. m. of pine and 3 080 cu. m. of oak) imposed by federal agencies is not even met—the locals don’t view that as a loss of potential revenue because the trees remain standing [1]. Few locally managed integrated conservation and resource extraction plans have been as impressive as the one in Ixtepeji.

Part of our purpose in being there was to try to trap a puma (Puma concolor) that had been preying upon livestock, most recently a calf, at a farm close to La Cumbre, on the other side of Highway 175. A three-kilometer hike from the restaurant brought us there. We went over a moderately steep ridge, fairly tough going after an inappropriately heavy breakfast. (Good food doesn’t contribute well to good natural history.) As is typical for this area, mixed oak and pine forest gave way to pure pine at the top, almost entirely Pinus oaxacana. It was wet, with Spanish moss and a bewildering variety of epiphytes adorning the trees. There were mushrooms everywhere of a variety of colors and sizes, and Victor duly noted that Mexico’s mushrooms remained poorly studied. (Wild mushrooms are harvested in Ixtepeji for export to Japan [1], and many varieties are locally consumed but it takes some experience to distinguish the edible ones from the poisonous. It is more than likely that there are mushroom species here that have yet to be scientifically described.) We continued to enjoy the remarkable—and remarkably little-studied—biodiversity of Oaxaca.

View of the Farm

Coping with the puma problem was another matter. The farmer claimed to have lost over US$ 1 000 in livestock during the last year or so, and was adamant that he would shoot the animal. (However, if that was his true intention, and he really did have the ability to carry it out, it remains somewhat mysterious why he hasn’t already done so.) Representatives from the La Cumbre Park suggested patience. The farmer asked for compensation for the lost livestock. No one stepped forward. We offered to lay our traps though I have my doubts that any of us had any confidence that these would succeed. The farmer had doubts, too: what if his animals wandered into his traps? An hour of negotiation led to a fairly predictable compromise. We would set the traps on the boundary of the farm where we would bait a shed in which the puma had previously killed a victim. The farmer would keep his animals off this area. If the puma is caught in the trap, we will be called to deal with it. But, if the puma is seen elsewhere in the farm, the farmer will try to shoot it.

We only had spring traps (each with a trigger plate and padded jaws) and were worried whether we’d injure the puma if we ever caught it. The traps were easy enough to set. You choose a likely path for the animal and anchor each trap with strong wire to some support which can resist the strength of a puma desperately trying to escape. You then dig a small hole in the ground and place the trap in it so that the trigger plate is roughly at ground level somewhere along the animal’s predicted path. Then you camouflage the trap by covering the plate and jaws lightly with earth, leaves, and other muck. (And you hope that it won’t rain—a single downpour would destroy any attempt at camouflage. You also hope that the jaws are firm enough to hold the animal but padded well enough not to maim it permanently.) We set about a half-dozen traps along paths leading to the shed. There’s nothing to prevent non-target species (other animals) from being caught in our traps. But the strangest part of our operation was that the bait used was a chicken. This was the Park officials’ choice, not ours. You’d hardly think that an animal apparently used to dining on cattle in the open would put much effort to extract a chicken from a shed.

Victor Sanchez-Cordero and Cecilia Londoño setting a puma trap. A calf had been killed here earlier.

No one was sure what we’d do with the puma if we caught it. The only two options were to confine it to a zoo or to release it elsewhere, perhaps within the Park. The trouble is that we had no idea whether it would come back to haunt the farm again. After all, it knows that there is food here. Wildlife-human conflicts are far from uncommon but what bothered me here was our lack of any baseline information. We didn’t have very good estimates on the number of pumas in the district. We didn’t know their home ranges in this region. In general, puma home ranges of females are supposed to range from 26 -350 sq. km. with an average of 140 sq. km. but there may be extensive overlap between home ranges of different females [2]. In contrast, male home ranges do not overlap and typically encompass the home ranges of two females. They range in size from 140 -760 sq. km. with an average of 280 sq. km. If the upper bounds of these ranges are typical in this region, releasing the puma in Ixtepeji would presumably achieve nothing. But the upper bounds may not be relevant here: ranges increase with a fall in prey density, and prey seemed relatively abundant here (though, once again, we had no hard data). We didn’t know if the offending puma was female or male—there were no pug marks.

We didn’t even know which of the ranges around us were part of home ranges of other pumas. Unless we began a program of collaring and tracking the local puma population—an expensive process, to say the least—our scientific methods offer little solace to the farmer. Conservation is fine, but not at the expense of the livelihood of the poor. The only rational plan at present seems to be the farmer’s: to shoot the offending animal. But the farmer is not entirely blameless. The area in which the puma has been attacking cattle is on the edge of the farm, bordering the forest which encloses the farm on all sides. This asks for trouble. Just as conservationists must address the concerns of the local inhabitants affected by efforts to save wild animals, the locals should not go out of their way to court trouble. Placing potential prey on the periphery of farms makes them vulnerable. We can hardly blame a puma for taking advantage of such carelessness. The farmer’s correct that there should be compensation for livestock lost to “conserved” animals, as there is in many parts of the world, for instance, parts of India. But this compensation should only be paid if there is no evidence of culpable carelessness.

(It’s been more than a week since we set the traps, and we haven’t heard anything of the puma. Presumably our efforts at capturing it have been a miserable failure, and the puma problem continues to fester in Ixtepeji.)